Abstract

The multiple localized surface plasmon resonances of nanorod dimers are theoretically investigated. The dark plasmon resonance of nanorod dimer aligned side-by-side is highly distance dependent. Based on this property, nanospheres are used to modify surface plasmon coupling between the two nanorods. The resonant wavelength shift increases approximately linearly with the increasing of nanospheres interparticle separations. This property makes such structure useful as plasmon ruler with homogeneous measurement sensitivity. The measurement range is increased to more than 100 nm, the resonant frequency is extended to the near-infrared region, and one can modify the structure size and nanorod aspect ratio freely to get the desired measurement range and sensitivity.

Received 31 May 2010Accepted 15 June 2010Published online 06 August 2010

Acknowledgments:

The authors thank Zong-Suo Zhang and Jian-Bo Li for the helpful discussion, and this work was supported by PIE under Grant No. 083307 and the Fund of Anhui Province for Young Teachers under Grant No. 2010SQRL037ZD.